This application claims the priority of German Application No. 101 06 150.1, filed Feb. 10, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a driving simulator, particularly for simulating the movements of earthbound vehicles. Earthbound vehicles include surface vehicles, such as road and rail vehicles, ships or aircraft on an airfield. Special embodiments of the driving simulator may also be used for simulating the movements of aircraft and spacecraft.
Driving simulators have been known for some time. In particular, a xe2x80x9csix-legged movement systemxe2x80x9d meets the requirements of the field of flight simulation. For fully dynamic simulations, this six-legged movement system is expanded with a carriage that moves in the x and y directions. It has been seen, however, that these movement systems are very complex, heavy and cost-intensive when employed in simulating the movements of earthbound vehicles. Moreover, this simulation method can only generate the forces and moments that occur in earthbound vehicles with an enormous power requirement.
The representation of accelerations by a movement system of a driving simulator is of fundamental significance for creating the experience of dynamic fringe maneuvers. In earthbound vehicles, the imaging of translatory accelerations in the simulation region requires a change from the real-life situation, because translatory movements from the comparatively xe2x80x9cinfinite dimension of the real roadway networkxe2x80x9d must be projected onto a finite dimension of a movement surface. The rotational degrees of freedom of movement, unlike the translatory degrees of freedom, can be imaged in their entirety and to a realistic extent in a more or less limited movement space, depending on the selected concept of the movement system.
It is the object of the present invention to provide a driving simulator that takes into account the special qualities of the movements of earthbound vehicles, and assures a particularly realistic simulation.
The inventive step essentially lies in moving an object (self-propelled carrier unit), which can receive a vehicle or a dummy vehicle, over an essentially horizontal floor surface in the required manner. An advantageous embodiment of the movement surface in a driving simulator of the invention is as a level surface, particularly a circular or oval-shaped surface, because in automobiles the tire-road adhesion permits accelerations of approximately equal magnitude in the longitudinal and transverse vehicle directions ([comb-type] frictional circle). The invention is also clearly distinguished from the six-legged system with the x and y carriage in that additional centrifugal forces due to circular driving patterns can be employed considerably more easily.
A notable feature of the driving-simulator concept in accordance with the invention is that the centrifugal accelerations occurring when the carrier unit (carrier platform) moves in circular patterns can also be used in principle to represent sustained longitudinal accelerations. Here, the longitudinal axis of the respective test vehicle (or dummy vehicle) supported on the carrier unit is oriented relative to the center point of the circle through a corresponding rotation of the carrier unit.
In accordance with the invention, the object is accomplished by providing a driving simulator, particularly for simulating the movements of earthbound vehicles and watercraft, having a carrier unit. The carrier unit includes a rigid floor platform, on which a test vehicle or a test dummy can be mounted. At least one projection surface (A) and at least one projector are provided. At least three movement modules are provided, each of which has a wheel that rolls on a floor surface and can be steered, relative to the axis extending perpendicular to the floor surface, by a first drive, and can be driven by a respectively associated second drive. In contrast to the aforementioned xe2x80x9csix-legged movement system,xe2x80x9d the concept of the present inventionxe2x80x94as indicated abovexe2x80x94is based on the movement system of a self-moving object, which takes into account the fact that the core movements of an earthbound vehicle are executed in the horizontal plane, while the vertical dimension only plays a secondary role.
The present driving simulator includes a carrier unit having a rigid floor in the form of a platform (floor platform), on which a test vehicle is mountedxe2x80x94for example, in the center of the platformxe2x80x94on its own wheels, or on which the dummy vehicle is mounted. The dummy vehicle can be embodied as a so-called xe2x80x9cmock-up,xe2x80x9d that is, a mechanical vehicle simulation or decoy, or as a mock seat, or a so-called xe2x80x9ccave,xe2x80x9d a virtual, three-dimensional representation of the vehicle. The carrier unit also has at least one projection surface, onto which at least one projector can project an image for a driving simulation.
The primary components of the carrier unit are movement modules, which permit a movement of the carrier unit, at least in the horizontal plane. Each movement module, which is preferably disposed at the periphery of the carrier unit or the floor platform, possesses a wheel or a twin wheel that rolls on a floor surface and can be steered by a first drive relative to the axis extending perpendicular to the floor platform. A second drive is provided for driving the wheel in the two directions of rotation.
The self-moving carrier unit requires at least three movement modules. To assure stability, it can be advantageous to use four or five preferably equidistantly-spaced movement modules. The independent guidance of the wheels in terms of their steering axle and the wheel drive itself allows for pure forward and backward movements, pure transverse movements, pure rotational movements, and combinations of these movements. The drives for the respective wheels are preferably disposed in the wheel hubs. This allows the drive to have an especially compact design. Each wheel can be used to generate a driving and a braking moment. The required braking moment may require the provision of an additional wheel-brake arrangement.
The notably circular carrier unit simultaneously constitutes an ideal base for a projection mounting or dome. In accordance with one embodiment, the projection dome is spherical or spherical-segment-shaped, and has at least one projection surface on its inside. The projection surface can also be designed for a 360xc2x0 simulation. For this purpose, appropriate projectors must be provided. In closed test vehicles, the projection can be limited to a horizontal ring of the semi-spherical surface, which is preferably to be dimensioned such that the driver""s eye position affords him a view of all of the viewing fields. For open vehicles, the projection could be effected in the manner of an xe2x80x9cOptimaxxe2x80x9d film. The projectors can preferably be disposed in the projection dome, particularly in the region of the zenith of the dome. Another option is rear projection, in which the projectors are disposed outside of the semi-spherical projection surface and project from the outside onto a semi-transparent projection screen. The number and arrangements of the projectors vary according to the type of projection.
A noise simulation can be effected, for example, with an audio system of a vehicle. In addition, the carrier unit, test vehicle or dummy vehicle can be equipped with further audio systems for locally simulating engine, rolling and wind noises.
Physical variables that are not actually present can therefore be simulated through visual impressions (projection surface), tactile impressions (vibrations) and acoustic impressions (noise simulation).
As mentioned above, the primary action in earthbound vehicles plays out in the horizontal region. When a vehicle moves on a road, however, vertical movements also occur due to uneven spots in the road surface or changes in the driving dynamics. If, in a first completed stage of the driving simulator, there is no display of a lifting degree of freedom, a lifting movement can be implemented in a further embodiment. It is thus possible to provide further drives in the individual movement modules for permitting a vertical movement of the floor platform of the carrier unit with respect to the floor surface. These drives can be conceptualized as hydraulic linear cylinders or hydraulic or electrical lifting-spindle drives.
As an alternative, or in addition, a corresponding lifting or lowering device can be provided in the floor platform of the carrier unit at, for example, the locations where the tires of the test vehicle are mounted on the carrier plates of the floor platform. In the structural embodiment of the respective lifting arrangement, it can be ensured that the lifting amplitude does not exceed an order of magnitude of 1 m in a use as a driving simulator. In a use as an air or space flight simulator, the lifting amplitude can be selected to be correspondingly larger. If the rolling and pitch degree of freedom of the vehicle movements is only passively realized in the first alternative because the vehicle mounted on the floor platform also produces lifting, rolling and pitch movements with its own chassis due to the acting acceleration forces, it is possible to initiate active lifting, rolling and pitching through the additional implementation of lifting devices in the second alternative. In this connection, it is important to note that the rolling and pitch axes are disposed at the height of the driver""s inner ear, so no misdirected acceleration information is supplied to the inner ear during unsteady lifting, rolling and pitch movements.
In both embodiments, it is necessary to tether the test vehicle to avoid an undesired displacement of the vehicle relative to the floor platform when acceleration forces are exerted. This tethering can be effected, for example, with restraining shackles or straps that connect the four wheel rims to four mounting plates of the floor platform.
These wheel-mounting plates, in turn, must permit a longitudinal and transverse displacement of the wheel-mounting surfaces in an order of magnitude of +/xe2x88x9220 mm so that the resilient movements of the vehicle chassis can be initiated extensively without causing a secondary bending movement of the wheel suspension. The mounting plates for the four wheels are therefore to be embodied, for example, in the form of sliding plates or pendulum-supported plates whose nonlinear elasticity always returns the wheel-mounting surfaces to the initial position in the event of a force-free movement state or an inoperative state of the driving simulator.
In accordance with a special embodiment, the carrier unit drives on a level floor surface of a simulation structure, which is preferably covered by a ceiling, dome or air-inflated structure. The level floor surface can be circular or oval-shaped, and, at least with respect to a navigable expansion, significantly larger than the dimensions of the carrier unit (e.g., about 8 m). The edges of the level surface can additionally be provided with safety devices, such as safety fences or safety cushions that prevent the carrier unit from moving beyond the floor surface.
A problem facing the structural design of the driving simulator according to the invention is how the carrier unit is to be supplied with power and information for the various drives, projectors, etc. In one version, this can be effected by embodying the carrier unit to be self-sufficient, in which case a power generator (e.g., an internal-combustion engine/generator unit) and calculation units that permit a corresponding movement with the associated simulation effects are installed in the carrier unit. Alternatively, it is possible to provide the carrier units with information externally. This can be effected, for example, by way of a radio connection. The power supply would have to be assumed by the carrier unit itself in this case. A different embodiment of the supply lies in running a connecting cable between the carrier unit and an element of an external environment, such as the simulation structure; here, both power and information can be supplied via the connecting cable.
The carrier unit can, however, also be supplied with power through pantographs (similarly to electric locomotives or city buses) that tap the electrical power, using sliding contacts, from a power system that spans the movement surface, and conduct the power back via the floor surface, which may be embodied as a ground pole.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.